Saw a picture of this done today, does anyone know the details of this and how to do it, can I just swap the bulbs and wiring over??

Indicators - Pull out your old - plug in the new.
Bulbs - just swap.
Wiring leave alone ;)

To remove just push the indicator towards the front of the car and the back edge will roll outwards.
Its easy to do, but if your not sure, just look at your new ones to see how their held in.

Somehow the question comes across as swapping the sidelight to become an indicator?
...

That's what I thought. I do remember a member called "Mole's Dad" doing this, but then he died tragically, after he'd done it, so I'm not sure how effective it was.

I'd THINK you could source some bulb holders of the correct type and do it fairly easily.

Alcazar

Very straightforward to convert to indicator but i'm not so sure on the bulbholder part.
Trying to fit a typical 21W indicator bulb into the sidelight ain't gonna work, so your left with using the wedge bulb which are 4 and 5W varieties.

I don't know if you can get higher wattage wedge bulbs, but maybe the LED type bulbs may give the necessary brightness?